1. Field of the Invention
The present invention relates to a cast-in element for forming a leadthrough for conduits and including a jacket tube and a base member having a space for receiving stop means and surrounding a through-opening of the cast-in element.
2. Description of the Prior Art
When planning and constructing buildings, on many occasions, leadthroughs for conduits, tubes, cables and the like are formed in walls and ceilings and only during a later constructional phase, e.g., during upgrade of the project, conduits are passed therethrough. In this way, damage of the tubes, cables or the like during earlier constructional phases is prevented. In order, e.g., to form a leadthrough in a ceiling, already during preparing a formwork, a tubular device with a desired diameter is secured on the formwork as a place-holder and, afterwards, remains cast in the cast constructional component such as concrete ceiling or concrete wall. The place-holder, thus, remains in the cast constructional component and projects past the cast constructional component at least on one side. The empty leadthroughs present a danger in case of fire as they can contribute to propagation of fire. Therefore, measure should be undertaken which would insure that the propagation of fire through the leadthrough is prevented at least for a predetermined minimal time period. To this end, the tubular devices contain in a space that surrounds the through-opening, e.g., a fire stopping mass that expands in case of fire and closes the leadthrough upon its expansion. With a flammable plastic tube, the intumescent mass prevents propagation of fire through the tube, while the tube crushes upon the expansion of the intumescent mass and closes the leadthrough. Such cast-in elements are formed of a one-piece housing, e.g., of plastic material and which, e.g., is cut to a length corresponding to the thickness of the to-be-produced constructional component.
A drawback of the known solution consists in that at large thicknesses of the constructional component, the required length of the cast-in element exceeds the length of conventionally produced cast-in elements. The user compensates these differences, e.g., with auxiliary elements which, however, often become unstable upon casting of the constructional component and/or which are associated with increased costs, in particular, connected with their proper attachment. From the economic point of view, manufacturing of a cast-in element that would cover at least the largest portion of the thickness of the constructional component, does not make sense because in many cases, a large section of a cast-in element would have to be cut off. In addition, with these cast-in elements, the cover for closing the through-opening can be mounted on the free end of the cast-in element during casting of the constructional component only using a formlocking connection. The cover must be secured on the cast-in element using additional means.
U.S. Publication US 2004/0016190 A1 discloses a cast-in element for forming a leadthrough for conduits and which includes a jacket tube and a base member connectable with the jacket tube. The base member has a receiving space for firestop means. The firestop means is an intumescent mass that expands in case of fire and closes the through-opening. The jacket tube is formed of a plurality of transverse bands connected by releasable connection means and held together by a holding section. A cover or a coupling is attached to the free end of the jacket tube with snap connection means.
The drawback of the cast-in element of the above-referenced publication consists in that the jacket tube can be brought to a desired length only in steps. Further, the manufacturing of the known cast-in element is expensive, which is a big drawback in mass production which the cast-in element represent.
Accordingly, an object of the present invention is a cast-in element for leadthroughs for conduits and which can be steplessly cut to a desired length and is modular in use.